Power swivel for use with concentric pipe strings

ABSTRACT

A power swivel for use with concentric drill pipe strings to enable rotation of an outer pipe string while operatively connected to a stationary inner pipe string for supplying power fluid to a turbine drill carried by the inner string.

United States Patent inventor Cicero C. Brown 5429 Sturbridge Drive,Houston, Tex. 77027 Appl. No. 70,425

Filed Sept. 8, 1970 Patented Nov. 30, 1971 POWER SWIVEL FOR USE WITHCONCENTRIC PIPE STRINGS 10 Claims, 7 Drawing Figs.

U.S. Cl 173/57, 173/163, 175/171, 175/173 F21b 3/02 173/57,

References Cited UNITED STATES PATENTS Hunt et a1. Graipin Brown Brownlshii FOREIGN PATENTS 2/1936 Germany 12/1967 GreatBritain PrimaryExaminer.lames A. Leppink Attorney-R. Werlin ABSTRACT: A power swivelfor use with concentric drill pipe strings to enable rotation of anouter pipe string while operatively connected to a stationary inner pipestring for supplying power fluid to a turbine drill carried by the innerstring.

PAIENTEnunv 30 Ian 3,623 .558

sum 3 or 4 ATTORNEY PATENTEUunv 30 l97l SHEET UF 4 POWER SWIVEL FOR USEWITH CONCENTRIC PIPE STRINGS BACKGROUND OF THE INVENTION In my U.S. Pat.No. 3,467,202, a hydraulically driven power head or swivel is disclosedfor rotating a conventional rotary drill string. In my copending US.Pat. application Ser. No. 778,509, filed Nov. 25, 1968, there isdisclosed a rotary drilling system employing casing as the drill pipestring and driven by a power swivel such as that disclosed in theaforementioned patent, the casing being equipped to receive a bitsection which is bodily insertable and removable through the bore ofthecasing.

While the casing-drilling system described in the aforementionedapplication is entirely successful, it is sometimes necessary to deviatethe borehole from the vertical in order to accomplish slant drilling, aswhen drilling a plurality of wells from a single location such as anoffshore platform. It is difficult to accomplish the desired deviationwhen using casing as the drill pipe and the present invention isdirected to a novel form of power swivel designed to meet this problem.

THE INVENTION In accordance with this invention there is provided apower swivel which is capable of rotating the casing drill string whilealso being operatively connected to a stationary drill string, ofsmaller diameter that the casing string, which extends through the boreof the casing string and is fitted with a turbine drill at its lower endto which operating fluid may be supplied through the power swivel.

With such a turbine drill string, it becomes possible to use the lattereither to drill straight ahead or to deviate the bore hole, while atsame time rotating the casing string to prevent sticking while drillingahead with the turbine drill.

In accordance with the illustrative embodiment of this invention, thepower swivel comprises a stationary headplate provided with a centralopening to receive a hollow spindle to be secured over the upper end ofthe outer casing string. Surrounding the spindle below the headplate isa drive n'ng mounted for axial and rotational movement relative to thespindle. Motor means, which may be hydraulic or electricpowered, aremounted on the headplate for reversibly driving the drive ring. Thelatter is connected to the spindle by means of a threaded connectionwhich permits limited axial movement relative to the spindle whiletransmitting rotational force to the spindle. The latter has pivotedelements mounted in the bore thereof for transmitting torsional force tothe casing string in response to angular movement of the spindle.

Pipe gripping elements are mounted to the spindle below thetorsion-transmitting elements and are actuated by the axial movement ofaslip bowl mounted to the drive ring to grip and release the casingstring.

The headplate of the power swivel carries hanger means mounted above thespindle for nonrotatably securing thereto a second smaller diameter pipestring which extends through the bore of the spindle and the casingstring. The second pipe string may be connected to a turbine drill fordeviating the bore hole or for drilling ahead of the casing string.

The power swivel is provided with appropriate conduits for transmittingpower fluid to the turbine drill and for circulating drilling and washfluid through the pipe strings as may be required.

The foregoing and other objects and advantages of this invention willbecome more readily apparent from the following detailed descriptionwhen read in conjunction with the accompanying drawing which illustratesa useful embodiment in accordance with this invention.

In the drawing:

FIG. 1 is a view partly in elevation and partly in vertical section ofthe improved power swivel, the drive connections to the casing stringbeing shown in retracted or disengaged positions;

FIG. 2 is a view similar to FIG. 1 showing the drive connection inengaged positions;

FIG. 3 is a perspective view, partly in section showing a turbine drillstring in borehole deviating position;

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 1;

FIGS. 5 and 6 are cross-sectional views taken respectively on lines 5-5and 6-6 ofFIG. 2; and

FIG. 7 is a view generally similar to FIG. 3 showing the casing stringin operation as the drill string in the absence of the inner turbinedrill string. Referring to the drawing:

The power swivel comprises an annular headplate 10 to the periphery ofwhich is secured a skirt 1]. Spider arms 12 attached to skirt ll securethe headplate to appropriate vertical guide bars 13 mounted in thederrick or like structure to hold headplate 10 stationary againstrotational forces. Headplate 10 has a central opening 14 to rotatablyreceive a tubular spindle designated generally by the numeral 15. Aspacer ring 16 is mounted on the top of headplate l0 concentric withopening 14 and radially spaced therefrom. A tabular hanger body 17 ismounted on spacer ring 16 and secured to headplate 19 by means of bolts18 which pass through the flange of body 17 and spacer ring 16 into theheadplate. A cap 19 is secured to the upper end of hanger body 18 bymeans of bolts 20 and has an axial bore 21 closed at its upper end abovewhich the cap is provided with a socket 22 to receive an eyebolt 23which is secured in socket 22 by a crosspin 24. Eyebolt 23 has an eye 25to receive the hook 26 carried by the usual traveling block (not shown)of a conventional drilling rig, by means of which the power swivel andits attached pipe strings may be raised, lowered and otherwisemanipulated as may be required.

Spindle 15 comprises a tubular body 30 having an axial bore 31. Anannular flange 32 is secured by means of bolts 34 to the upper end ofbody 30 and its outer periphery projects into the annular space betweenthe upper end of body 30 and spacer ring 16. Roller bearings 33 arepositioned between the outer extension of flange 32 and the uppersurface of plate I0 between the opposed surfaces of body 30 and spacerring I6. Bore 31 is adapted to receive the upper end of a string ofcasing P which carries a conventional threaded collar C in abuttingengagement with a shoulder 35 provided in bore 31.

An annular drive ring, designated generally by the numeral 40, isdisposed in spaced relation below headplate l0 and comprises an annularhorizontally disposed bottom plate 41 having an upstanding annular hub42 about its inner periphery surrounding spindle I5 and an upstandingring gear 43 having internal teeth 44 mounted on its outer rim to extendslidably inside skirt 11. A plurality of reversible hydraulic motors 45,of conventional design, are mounted on headplate l0. Motors 45 whichalso may be pneumatic or electric-powered, are connected to downwardlyextending drive shafts 46 carrying pinions 47 whose teeth 48 are in meshwith teeth 44 of the ring gear and arranged to permit relative axialmovement of the ring gear while in mesh with the pinions. The pinionsare supported on the ends of shafts 46 by a bearing plate 49 which issecured to headplate 10 by means of hanger bolts 50 extending throughspacer sleeves 51.

A section of external threads 52 is formed on the upper end portion ofhub 42 and are in continuous mesh with a section of complementarythreads 53 formed on the exterior of spindle body 30 and substantiallygreater in length than the section of threads 52. This threadedconnection provides the primary rotary drive connection between drivering 40 and spindle 15. As a result of the difference in length betweenthread sections 52 and 53, rotation of the drive ring will initiallyproduce limited axial movement of the drive ring relative to the spindlefrom its lowermost position (FIG. 1) to its uppermost position (FIG. 2),for purposes to be described hereinafter. When the latter position hasbeen attained, continued rotation of the drive ring will transmitrotational force to the spindle.

For transmitting torsional force to casing string P, swivel body 30 isprovided with an annular recess 36 in its bore wall located at a pointwhich will be opposite collar C when the latter has been received in thebore of the spindle in abutting relation to shoulder 35. As best seen inFIGS. 4 and 5, a pair of arcuate pipe-gripping dogs 37, oppositelydisposed in recess 36, are rockably mounted about vertically extendingshafts 38 and are provided on their inner faces with pipe-gripping teeth38a and on their outer faces with smooth arcuate surfaces 38b whichtaper inwardly toward their opposite ends. The inner wall of recess 36is formed on opposite sides thereof with cam surfaces 39 which cooperatewith tapered arcuate surfaces 380 of the dogs 37 to rock them into andout of gripping engagement with collarC in accordance with the directionof angular movement of the spindle produced by rotation of drive ring40. An outwardly bowed leaf spring 54 is mounted to extendlongitudinally of the center of the inner face of each dog 37 to bearagainst collar C and bias the dog toward the camengaging position (FIG.and thereby assure gripping of the collar in response to the angularmovement of the spindle.

Mounted to the lower end of spindle body 30 for radial movement relativethereto is a plurality of circumferential spaced wedge-shapedpipe-gripping slips 55 carrying toothed dies 56 on their inner faces andformed with downwardly and inwardly tapering backfaces 57. The upperends of the slips are formed with T-shaped heads 58 slidably receivablein correspondingly shaped hangers 59 depending from the lower end of thebody 30, this arrangement permitting the aforesaid radial movement ofthe slips relative to spindle body 30.

A slip bowl 60 having a downwardly and inwardly tapering slip-engagingbore 61 complementing the taper of backfaces 57 of the slips is mountedto bottom plate 41 of the drive ring in surrounding relation to slips55. Dovetail screwheads 62 project from bore 61 into dovetail slots 63extending longitudinally of backfaces 57 of the slips and formlongitudinally slidable connections between the slips and slip bowlwhich will constrain radial movement of the slips in response torelative longitudinal movement of the slip bowl. The upper end of theslip bowl carries an outwardly extending annular flange 64 which isrotatably received in a correspondingly shaped annular recess 64a fonnedin the inner periphery of a hanger ring 64b which is secured by means ofbolts 64c to the lower face of bottom plate 41 of the drive ring.

An annular recess 65 is provided in the bore of cap 19 immediately abovethe upper end of hanger body 17 to receive a correspondingly shapedannular lug 66 formed about the exterior of an internally threaded box67 carried by the upper end of a connector nipple 68, which extendscoaxially through the bore of spindle and is smaller in diameter thancasing string P. The lower end of nipple 68 carries an externallythreaded pin member 69 for attachment to the upper end of a secondstring of pipe D which extends through casing string C and may beconnected to a conventional turbine drill T (FIG. 3) for purposes to bedescribed hereinafter.

A plurality of hanger pins 70 are threaded radially through the lowerend of cap 19 and are adapted to be retractably received in a lockinggroove 71 formed in the wall of recess 65 to releasably lock box 67 inthe hanger.

A port 72 through the wall of cap 19 provides fluid communication withbore 21 and thence with the bore of connector nipple 68 and is connectedto a conduit 73. Another port 74 through the wall of hanger body 17below box 67 provides fluid communication with the annular space betweenconnector nipple 68 and casing string P and is connected to a secondconduit 75. By means of ports 72 and 74 and their respective conduits 73and 7S, fluid may be circulated to and from each of the pipe strings asmay be found necessary or desirable in connection with the variousoperations performed by the power swivel. I

OPERATION As indicated previously, the power swivel is capable ofmultiple operations. It may be employed in a casing drilling system torotate casing string P as a rotary drill string to drive a bit section B(FIG. 7) which is insertable bodily through the bore of the casingstring and landed in a suitable landing nipple N therein, the bitsection comprising a pilot bit and expansible underreamers. Such asystem is fully described in my copending U.S. application. Ser. No.778,509, filed Nov. 25, l. 968.

When so employed connector nipple 68 may be kept in place as seen inFIGS. 1 and 2 or removed from the power swivel assemblage. Removal ofthe connector nipple is easily effected by unbolting cap 19, retractinghanger screws and lifting the connector nipple out of hanger body 17,after which cap 19 is reattached to the hanger body.

When used to drive casing string P, the swivel will be lowered overcollar C to insert the latter into spindle 15 until the upper end of thecollar abuts shoulder 35. At this stage of operations drive ring 40 willbe in its lower or retracted position, as seen in FIG. 1. In thisposition slip bowl 60 will be in its lowered position and slips 55retracted. Rotation of the drive ring by operation of motors 45 will notbe started. The first results of this rotation will be to cause drivering 40 and its appurtenances to move upwardly by reason of the threadedconnection between hub 42 and spindle 15 which temporarily, will be heldrelatively stationary by reason of frictional forces between the spindleand the stationary elements of the power swivel. As the drive ring movesupwardly to the limit of the threaded connection to the spindle, slipbowl 60 will be drawn upwardly and will translate this upward movementto radial movement of slips 55 until the latter are driven intotightgripping engagement with casing string 1-". At the same time therotation of the drive ring will actuate dogs 37 to their pipegrippingposition (FIGS. 2 and 5) so that continued rotation of drive ring 40will transmit torsional force to collar C and casing string P to producethe desired rotation of the casing string and its connected bit sectionfor drilling a borehole W (FIG. 7).

When it is desired to operate a turbine drill from the power swivel, aswhen necessary to effect a deviation of the borehole from the verticalto permit slant drilling, connector nipple 68 will be installed in thepower swivel, if not already in place, and will be connected to thesmaller diameter string of pipe D carrying the turbine drill T whichwill have been extended through the bore of easing string P (FIG. 3)from which hit section B will have been removed. Pressure fluid may thenbe circulated through conduit 73 to drive the turbine drill, the returnfluid flowing through the annulus between casing string P and pipestring D to the surface and discharging through conduit 75.

At the same time, it is desirable to rotate casing string P in order toprevent its sticking while the turbine drill is drilling ahead and toadvance the casing string along the borehole with the advance of theturbine drill. This dual operation can be readily accomplished byoperating the power swivel as previously described to rotate casingstring P while the inner pipe string D remains stationary rotationallywhile both pipe strings advance axially behind the turbine drill.

Addition or removal of sections of the dual pipe strings when runninginto and out of the well bore may be effected by generally conventionaland well-known procedures.

Reverse rotation of the drive ring will produce downward movementthereof relative to the spindle, lowering slip bowl 60 and retractingslips 55 and reversing dogs 37 to thereby release the attachment of theswivel to casing string P when necessary or desired to enable additionor removal of sections of the pipe strings.

From the foregoing, it will be evident that the abovedescribed powerswivel may be employed for multiple drilling uses. It will be understoodthat various changes and modifications may be made in the details of theillustrative embodiment within the scope of the appended claims butwithout departing from the spirit of this invention.

Whatl claim and desire to secure by Letters Patent is:

l. A power swivel for dual concentric pipe strings comprismg:

a. a stationary annular headplate having a central opening;

b. a hollow spindle rotatably mounted in said opening and adapted toreceive the upper end of a first pipe string;

c. hanger means on the headplate for securing thereto a second pipestring extending through the bore of said first pipe string innonrotative relation thereto;

d. a drive ring disposed about said spindle below said headplate foraxial and rotational movement relative thereto;

e. reversible motor means mounted on the headplate and drivinglyconnected to said drive ring;

f. a drive connection between said drive ring and said spindle includinga threaded section affording limited axial movement of the drive ringrelative to the spindle in response to relative rotation therebetween;and

g. means mounted on said spindle for transmitting torsional forcetherefrom to said first pipe string.

2. A power swivel according to claim 1 including; pipegripping elementsmounted to said spindle below said means for transmitting torsionalforce and arranged for radial movement into and out of grippingengagement with said first pipe string in response to said limited axialmovement of said drive ring.

3. A power swivel according to claim 2 wherein said pipegrippingelements include:

a. a plurality of angularly spaced pipe-gripping wedges having radiallyslidable connection to the lower end of said spindle; and

b. a tapered slip bowl mounted to rounding relation to said wedges.

4. A power swivel according to claim 1 wherein said drive ring includes:

a. an internally toothed ring gear disposed about its outer peripheryand meshing with pinions driven by said motor means; and

b. a tubular hub surrounding said spindle and a carrying thread sectionin mesh with a longer thread section on said spindle.

5. A power swivel according to claim 1 wherein said hanger meansincludes:

a. a tubular hanger body having an annular recess in the bore thereof;

b. a connector nipple disposed coaxially through said bore and having anannular lug seatable in said recess; and

c. retractable hanger pins threaded radially through said hanger bodyfor movement into and out of locking engagement with said connectornipple.

6. A power swivel according to claim I wherein said lastmentioned meansincludes:

a. arcuate dogs having toothed inner faces and smoothly tapered outerfaces rockably mounted in angularly spaced relation in the bore of saidspindle; and

b. cam surfaces in the bore of said spindle cooperating with saidtapered outer faces of said dogs to rock said dogs into and out ofgripping engagement with said first pipe string in response to angularmovement of said spindle.

7. A power swivel according to claim 1 including means carried by saidheadplate for separately providing fluid communication with therespective pipe strings.

8. A power swivel for dual concentric pipe strings comprissaid drivering in suring:

a. a stationary annular headplate having a central opening;

b. a hollow spindle vertically disposed for rotation in said opening andadapted to receive the upper end of a first pipe string;

. a drive ring disposed about said spindle below said headplate foraxial and rotational movement relative thereto;

d. motor means mounted on the headplate and drivingly connected to saiddrive ring;

e. means mounted in the bore of said spindle for transmitting torsiontherefrom to said first pipe string;

f. a drive connection between said drive ring and said spindle includinga threaded section affording limited axial movement of the drive ringrelative to the spindle;

g. pipe-gripping elements mounted to said spindle below saidtorsion-transmitting means for radial movement into an out of grippingengagement with said first pipe string in response to said limited axialmovement of said drive ring; and

h. hanger means on the headplate for securing thereto a second pipestring extending through the bore of said first pipe string.

9. A power swivel according to claim 8 including means carried by saidheadplate for separately providing fluid communication with therespective pipe strings.

10. A power swivel for dual concentric pipe strings comprising:

a. a stationary annular headplate having a central opening;

b. a tubular spindle vertically disposed for rotation in said openingand adapted to receive the upper end of a first pipe string;

means mounted in the bore of said spindle for transmitting torsiontherefrom to said first pipe string;

d. a drive ring disposed below said headplate surrounding the spindlefor axial and rotational movement relative to said headplate;

e. complementary thread means connecting said drive ring to said spindlefor limited vertical movement relative thereto in response to rotationalmovement of the drive ring;

motor means mounted on the headplate and drivingly connected to saiddrive rings;

g. a downwardly tapering slip bowl depending from said drive ring;

. a plurality of pipe-gripping wedges mounted to said spindle andextending into said slip bowl for radial movement into and out ofgripping engagement with said first pipe string in response to axialmovements of said slip bowl;

. hanger means on the headplate for securing thereto a second pipestring extending through the bore of the first pipe string; and

. means carried by said head plate for separately providing fluidcommunication with each of said pipe strings.

1. A power swivel for dual concentric pipe strings comprising: a. astationary annular headplate having a central opening; b. a hollowspindle rotatably mounted in said opening and adapted to receive theupper end of a first pipe string; c. hanger means on the headplate forsecuring thereto a second pipe string extending through the bore of saidfirst pipe string in nonrotative relation thereto; d. a drive ringdisposed about said spindle below said headplate for axial androtational movement relative thereto; e. reversible motor means mountedon the headplate and drivingly connected to said drive ring; f. a driveconnection between said drive ring and said spindle including a threadedsection affording limited axial movement of the drive ring relative tothe spindle in response to relative rotation therebetween; and g. meansmounted on said spindle for transmitting torsional force therefrom tosaid first pipe string.
 2. A power swivel according to claim 1Including: pipe-gripping elements mounted to said spindle below saidmeans for transmitting torsional force and arranged for radial movementinto and out of gripping engagement with said first pipe string inresponse to said limited axial movement of said drive ring.
 3. A powerswivel according to claim 2 wherein said pipe-gripping elements include:a. a plurality of angularly spaced pipe-gripping wedges having radiallyslidable connection to the lower end of said spindle; and b. a taperedslip bowl mounted to said drive ring in surrounding relation to saidwedges.
 4. A power swivel according to claim 1 wherein said drive ringincludes: a. an internally toothed ring gear disposed about its outerperiphery and meshing with pinions driven by said motor means; and b. atubular hub surrounding said spindle and a carrying thread section inmesh with a longer thread section on said spindle.
 5. A power swivelaccording to claim 1 wherein said hanger means includes: a. a tubularhanger body having an annular recess in the bore thereof; b. a connectornipple disposed coaxially through said bore and having an annular lugseatable in said recess; and c. retractable hanger pins threadedradially through said hanger body for movement into and out of lockingengagement with said connector nipple.
 6. A power swivel according toclaim 1 wherein said last-mentioned means includes: a. arcuate dogshaving toothed inner faces and smoothly tapered outer faces rockablymounted in angularly spaced relation in the bore of said spindle; and b.cam surfaces in the bore of said spindle cooperating with said taperedouter faces of said dogs to rock said dogs inTo and out of grippingengagement with said first pipe string in response to angular movementof said spindle.
 7. A power swivel according to claim 1 including meanscarried by said headplate for separately providing fluid communicationwith the respective pipe strings.
 8. A power swivel for dual concentricpipe strings comprising: a. a stationary annular headplate having acentral opening; b. a hollow spindle vertically disposed for rotation insaid opening and adapted to receive the upper end of a first pipestring; c. a drive ring disposed about said spindle below said headplatefor axial and rotational movement relative thereto; d. motor meansmounted on the headplate and drivingly connected to said drive ring; e.means mounted in the bore of said spindle for transmitting torsiontherefrom to said first pipe string; f. a drive connection between saiddrive ring and said spindle including a threaded section affordinglimited axial movement of the drive ring relative to the spindle; g.pipe-gripping elements mounted to said spindle below saidtorsion-transmitting means for radial movement into an out of grippingengagement with said first pipe string in response to said limited axialmovement of said drive ring; and h. hanger means on the headplate forsecuring thereto a second pipe string extending through the bore of saidfirst pipe string.
 9. A power swivel according to claim 8 includingmeans carried by said headplate for separately providing fluidcommunication with the respective pipe strings.
 10. A power swivel fordual concentric pipe strings comprising: a. a stationary annularheadplate having a central opening; b. a tubular spindle verticallydisposed for rotation in said opening and adapted to receive the upperend of a first pipe string; c. means mounted in the bore of said spindlefor transmitting torsion therefrom to said first pipe string; d. a drivering disposed below said headplate surrounding the spindle for axial androtational movement relative to said headplate; e. complementary threadmeans connecting said drive ring to said spindle for limited verticalmovement relative thereto in response to rotational movement of thedrive ring; f. motor means mounted on the headplate and drivinglyconnected to said drive rings; g. a downwardly tapering slip bowldepending from said drive ring; h. a plurality of pipe-gripping wedgesmounted to said spindle and extending into said slip bowl for radialmovement into and out of gripping engagement with said first pipe stringin response to axial movements of said slip bowl; i. hanger means on theheadplate for securing thereto a second pipe string extending throughthe bore of the first pipe string; and j. means carried by said headplate for separately providing fluid communication with each of saidpipe strings.